Re: [PATCH v2 1/9] llist: Provide a safe version for llist_for_each

[Huang, Ying]

Byungchul Park  writes:

> On Mon, Feb 13, 2017 at 04:58:05PM +0900, Byungchul Park wrote:
>> On Mon, Feb 13, 2017 at 03:52:44PM +0800, Huang, Ying wrote:
>> > Byungchul Park  writes:
>> > 
>> > > On Mon, Feb 13, 2017 at 03:36:33PM +0800, Huang, Ying wrote:
>> > >> Byungchul Park  writes:
>> > >> 
>> > >> > Sometimes we have to dereference next field of llist node before 
>> > >> > entering
>> > >> > loop becasue the node might be deleted or the next field might be
>> > >> > modified within the loop. So this adds the safe version of 
>> > >> > llist_for_each,
>> > >> > that is, llist_for_each_safe.
>> > >> >
>> > >> > Signed-off-by: Byungchul Park 
>> > >> > ---
>> > >> >  include/linux/llist.h | 19 +++
>> > >> >  1 file changed, 19 insertions(+)
>> > >> >
>> > >> > diff --git a/include/linux/llist.h b/include/linux/llist.h
>> > >> > index fd4ca0b..4c508a5 100644
>> > >> > --- a/include/linux/llist.h
>> > >> > +++ b/include/linux/llist.h
>> > >> > @@ -105,6 +105,25 @@ static inline void init_llist_head(struct 
>> > >> > llist_head *list)
>> > >> >   for ((pos) = (node); pos; (pos) = (pos)->next)
>> > >> >  
>> > >> >  /**
>> > >> > + * llist_for_each_safe - iterate over some deleted entries of a 
>> > >> > lock-less list
>> > >> > + *safe against removal of list entry
>> > >> > + * @pos: the  llist_node to use as a loop cursor
>> > >> > + * @n:   another type * to use as temporary storage
>> > >> 
>> > >> s/type */ llist_node/
>> > >
>> > > Yes.
>> > >
>> > >> 
>> > >> > + * @node:the first entry of deleted list entries
>> > >> > + *
>> > >> > + * In general, some entries of the lock-less list can be traversed
>> > >> > + * safely only after being deleted from list, so start with an entry
>> > >> > + * instead of list head.
>> > >> > + *
>> > >> > + * If being used on entries deleted from lock-less list directly, the
>> > >> > + * traverse order is from the newest to the oldest added entry.  If
>> > >> > + * you want to traverse from the oldest to the newest, you must
>> > >> > + * reverse the order by yourself before traversing.
>> > >> > + */
>> > >> > +#define llist_for_each_safe(pos, n, node)\
>> > >> > + for ((pos) = (node); (pos) && ((n) = (pos)->next, true); (pos) 
>> > >> > = (n))
>> > >> > +
>> > >> 
>> > >> Following the style of other xxx_for_each_safe,
>> > >> 
>> > >> #define llist_for_each_safe(pos, n, node)   \
>> > >> for (pos = (node), (pos && (n = pos->next)); pos; pos = n, n = 
>> > >> pos->next)
>> > >
>> > > Do you think it should be modified? I think mine is simpler. No?
>> > 
>> > Personally I prefer the style of other xxx_for_each_safe().
>> 
>> Yes, I will modify it as you recommand.
>> 
>> Thank you very much.
>
> I wanted to modify it as you recommanded but it has a bug. It should be
> (to fix the bug):
>
>for (pos = (node), (pos && (n = pos->next)); pos; pos = n, (pos && \
>(n = pos->next)))
>
> Don't you think this is too messy? Or do I miss something? I still think
> the following is neater and simpler.
>
>for (pos = node; pos && (n = pos->next, true); pos = n)

OK.  This looks better.

Best Regards,
Huang, Ying

> Or could you recommand another preference?

Re: [PATCH v2 1/9] llist: Provide a safe version for llist_for_each

[Huang, Ying]

Byungchul Park  writes:

> On Mon, Feb 13, 2017 at 04:58:05PM +0900, Byungchul Park wrote:
>> On Mon, Feb 13, 2017 at 03:52:44PM +0800, Huang, Ying wrote:
>> > Byungchul Park  writes:
>> > 
>> > > On Mon, Feb 13, 2017 at 03:36:33PM +0800, Huang, Ying wrote:
>> > >> Byungchul Park  writes:
>> > >> 
>> > >> > Sometimes we have to dereference next field of llist node before 
>> > >> > entering
>> > >> > loop becasue the node might be deleted or the next field might be
>> > >> > modified within the loop. So this adds the safe version of 
>> > >> > llist_for_each,
>> > >> > that is, llist_for_each_safe.
>> > >> >
>> > >> > Signed-off-by: Byungchul Park 
>> > >> > ---
>> > >> >  include/linux/llist.h | 19 +++
>> > >> >  1 file changed, 19 insertions(+)
>> > >> >
>> > >> > diff --git a/include/linux/llist.h b/include/linux/llist.h
>> > >> > index fd4ca0b..4c508a5 100644
>> > >> > --- a/include/linux/llist.h
>> > >> > +++ b/include/linux/llist.h
>> > >> > @@ -105,6 +105,25 @@ static inline void init_llist_head(struct 
>> > >> > llist_head *list)
>> > >> >   for ((pos) = (node); pos; (pos) = (pos)->next)
>> > >> >  
>> > >> >  /**
>> > >> > + * llist_for_each_safe - iterate over some deleted entries of a 
>> > >> > lock-less list
>> > >> > + *safe against removal of list entry
>> > >> > + * @pos: the  llist_node to use as a loop cursor
>> > >> > + * @n:   another type * to use as temporary storage
>> > >> 
>> > >> s/type */ llist_node/
>> > >
>> > > Yes.
>> > >
>> > >> 
>> > >> > + * @node:the first entry of deleted list entries
>> > >> > + *
>> > >> > + * In general, some entries of the lock-less list can be traversed
>> > >> > + * safely only after being deleted from list, so start with an entry
>> > >> > + * instead of list head.
>> > >> > + *
>> > >> > + * If being used on entries deleted from lock-less list directly, the
>> > >> > + * traverse order is from the newest to the oldest added entry.  If
>> > >> > + * you want to traverse from the oldest to the newest, you must
>> > >> > + * reverse the order by yourself before traversing.
>> > >> > + */
>> > >> > +#define llist_for_each_safe(pos, n, node)\
>> > >> > + for ((pos) = (node); (pos) && ((n) = (pos)->next, true); (pos) 
>> > >> > = (n))
>> > >> > +
>> > >> 
>> > >> Following the style of other xxx_for_each_safe,
>> > >> 
>> > >> #define llist_for_each_safe(pos, n, node)   \
>> > >> for (pos = (node), (pos && (n = pos->next)); pos; pos = n, n = 
>> > >> pos->next)
>> > >
>> > > Do you think it should be modified? I think mine is simpler. No?
>> > 
>> > Personally I prefer the style of other xxx_for_each_safe().
>> 
>> Yes, I will modify it as you recommand.
>> 
>> Thank you very much.
>
> I wanted to modify it as you recommanded but it has a bug. It should be
> (to fix the bug):
>
>for (pos = (node), (pos && (n = pos->next)); pos; pos = n, (pos && \
>(n = pos->next)))
>
> Don't you think this is too messy? Or do I miss something? I still think
> the following is neater and simpler.
>
>for (pos = node; pos && (n = pos->next, true); pos = n)

OK.  This looks better.

Best Regards,
Huang, Ying

> Or could you recommand another preference?

Re: [PATCH v2 1/9] llist: Provide a safe version for llist_for_each

[Byungchul Park]

On Mon, Feb 13, 2017 at 04:58:05PM +0900, Byungchul Park wrote:
> On Mon, Feb 13, 2017 at 03:52:44PM +0800, Huang, Ying wrote:
> > Byungchul Park  writes:
> > 
> > > On Mon, Feb 13, 2017 at 03:36:33PM +0800, Huang, Ying wrote:
> > >> Byungchul Park  writes:
> > >> 
> > >> > Sometimes we have to dereference next field of llist node before 
> > >> > entering
> > >> > loop becasue the node might be deleted or the next field might be
> > >> > modified within the loop. So this adds the safe version of 
> > >> > llist_for_each,
> > >> > that is, llist_for_each_safe.
> > >> >
> > >> > Signed-off-by: Byungchul Park 
> > >> > ---
> > >> >  include/linux/llist.h | 19 +++
> > >> >  1 file changed, 19 insertions(+)
> > >> >
> > >> > diff --git a/include/linux/llist.h b/include/linux/llist.h
> > >> > index fd4ca0b..4c508a5 100644
> > >> > --- a/include/linux/llist.h
> > >> > +++ b/include/linux/llist.h
> > >> > @@ -105,6 +105,25 @@ static inline void init_llist_head(struct 
> > >> > llist_head *list)
> > >> >for ((pos) = (node); pos; (pos) = (pos)->next)
> > >> >  
> > >> >  /**
> > >> > + * llist_for_each_safe - iterate over some deleted entries of a 
> > >> > lock-less list
> > >> > + * safe against removal of list entry
> > >> > + * @pos:  the  llist_node to use as a loop cursor
> > >> > + * @n:another type * to use as temporary storage
> > >> 
> > >> s/type */ llist_node/
> > >
> > > Yes.
> > >
> > >> 
> > >> > + * @node: the first entry of deleted list entries
> > >> > + *
> > >> > + * In general, some entries of the lock-less list can be traversed
> > >> > + * safely only after being deleted from list, so start with an entry
> > >> > + * instead of list head.
> > >> > + *
> > >> > + * If being used on entries deleted from lock-less list directly, the
> > >> > + * traverse order is from the newest to the oldest added entry.  If
> > >> > + * you want to traverse from the oldest to the newest, you must
> > >> > + * reverse the order by yourself before traversing.
> > >> > + */
> > >> > +#define llist_for_each_safe(pos, n, node) \
> > >> > +  for ((pos) = (node); (pos) && ((n) = (pos)->next, true); (pos) 
> > >> > = (n))
> > >> > +
> > >> 
> > >> Following the style of other xxx_for_each_safe,
> > >> 
> > >> #define llist_for_each_safe(pos, n, node)\
> > >>  for (pos = (node), (pos && (n = pos->next)); pos; pos = n, n = 
> > >> pos->next)
> > >
> > > Do you think it should be modified? I think mine is simpler. No?
> > 
> > Personally I prefer the style of other xxx_for_each_safe().
> 
> Yes, I will modify it as you recommand.
> 
> Thank you very much.

I wanted to modify it as you recommanded but it has a bug. It should be
(to fix the bug):

   for (pos = (node), (pos && (n = pos->next)); pos; pos = n, (pos && \
   (n = pos->next)))

Don't you think this is too messy? Or do I miss something? I still think
the following is neater and simpler.

   for (pos = node; pos && (n = pos->next, true); pos = n)

Or could you recommand another preference?

Re: [PATCH v2 1/9] llist: Provide a safe version for llist_for_each

[Byungchul Park]

On Mon, Feb 13, 2017 at 04:58:05PM +0900, Byungchul Park wrote:
> On Mon, Feb 13, 2017 at 03:52:44PM +0800, Huang, Ying wrote:
> > Byungchul Park  writes:
> > 
> > > On Mon, Feb 13, 2017 at 03:36:33PM +0800, Huang, Ying wrote:
> > >> Byungchul Park  writes:
> > >> 
> > >> > Sometimes we have to dereference next field of llist node before 
> > >> > entering
> > >> > loop becasue the node might be deleted or the next field might be
> > >> > modified within the loop. So this adds the safe version of 
> > >> > llist_for_each,
> > >> > that is, llist_for_each_safe.
> > >> >
> > >> > Signed-off-by: Byungchul Park 
> > >> > ---
> > >> >  include/linux/llist.h | 19 +++
> > >> >  1 file changed, 19 insertions(+)
> > >> >
> > >> > diff --git a/include/linux/llist.h b/include/linux/llist.h
> > >> > index fd4ca0b..4c508a5 100644
> > >> > --- a/include/linux/llist.h
> > >> > +++ b/include/linux/llist.h
> > >> > @@ -105,6 +105,25 @@ static inline void init_llist_head(struct 
> > >> > llist_head *list)
> > >> >for ((pos) = (node); pos; (pos) = (pos)->next)
> > >> >  
> > >> >  /**
> > >> > + * llist_for_each_safe - iterate over some deleted entries of a 
> > >> > lock-less list
> > >> > + * safe against removal of list entry
> > >> > + * @pos:  the  llist_node to use as a loop cursor
> > >> > + * @n:another type * to use as temporary storage
> > >> 
> > >> s/type */ llist_node/
> > >
> > > Yes.
> > >
> > >> 
> > >> > + * @node: the first entry of deleted list entries
> > >> > + *
> > >> > + * In general, some entries of the lock-less list can be traversed
> > >> > + * safely only after being deleted from list, so start with an entry
> > >> > + * instead of list head.
> > >> > + *
> > >> > + * If being used on entries deleted from lock-less list directly, the
> > >> > + * traverse order is from the newest to the oldest added entry.  If
> > >> > + * you want to traverse from the oldest to the newest, you must
> > >> > + * reverse the order by yourself before traversing.
> > >> > + */
> > >> > +#define llist_for_each_safe(pos, n, node) \
> > >> > +  for ((pos) = (node); (pos) && ((n) = (pos)->next, true); (pos) 
> > >> > = (n))
> > >> > +
> > >> 
> > >> Following the style of other xxx_for_each_safe,
> > >> 
> > >> #define llist_for_each_safe(pos, n, node)\
> > >>  for (pos = (node), (pos && (n = pos->next)); pos; pos = n, n = 
> > >> pos->next)
> > >
> > > Do you think it should be modified? I think mine is simpler. No?
> > 
> > Personally I prefer the style of other xxx_for_each_safe().
> 
> Yes, I will modify it as you recommand.
> 
> Thank you very much.

I wanted to modify it as you recommanded but it has a bug. It should be
(to fix the bug):

   for (pos = (node), (pos && (n = pos->next)); pos; pos = n, (pos && \
   (n = pos->next)))

Don't you think this is too messy? Or do I miss something? I still think
the following is neater and simpler.

   for (pos = node; pos && (n = pos->next, true); pos = n)

Or could you recommand another preference?

Re: [PATCH v2 1/9] llist: Provide a safe version for llist_for_each

[Byungchul Park]

On Mon, Feb 13, 2017 at 03:52:44PM +0800, Huang, Ying wrote:
> Byungchul Park  writes:
> 
> > On Mon, Feb 13, 2017 at 03:36:33PM +0800, Huang, Ying wrote:
> >> Byungchul Park  writes:
> >> 
> >> > Sometimes we have to dereference next field of llist node before entering
> >> > loop becasue the node might be deleted or the next field might be
> >> > modified within the loop. So this adds the safe version of 
> >> > llist_for_each,
> >> > that is, llist_for_each_safe.
> >> >
> >> > Signed-off-by: Byungchul Park 
> >> > ---
> >> >  include/linux/llist.h | 19 +++
> >> >  1 file changed, 19 insertions(+)
> >> >
> >> > diff --git a/include/linux/llist.h b/include/linux/llist.h
> >> > index fd4ca0b..4c508a5 100644
> >> > --- a/include/linux/llist.h
> >> > +++ b/include/linux/llist.h
> >> > @@ -105,6 +105,25 @@ static inline void init_llist_head(struct 
> >> > llist_head *list)
> >> >  for ((pos) = (node); pos; (pos) = (pos)->next)
> >> >  
> >> >  /**
> >> > + * llist_for_each_safe - iterate over some deleted entries of a 
> >> > lock-less list
> >> > + *   safe against removal of list entry
> >> > + * @pos:the  llist_node to use as a loop cursor
> >> > + * @n:  another type * to use as temporary storage
> >> 
> >> s/type */ llist_node/
> >
> > Yes.
> >
> >> 
> >> > + * @node:   the first entry of deleted list entries
> >> > + *
> >> > + * In general, some entries of the lock-less list can be traversed
> >> > + * safely only after being deleted from list, so start with an entry
> >> > + * instead of list head.
> >> > + *
> >> > + * If being used on entries deleted from lock-less list directly, the
> >> > + * traverse order is from the newest to the oldest added entry.  If
> >> > + * you want to traverse from the oldest to the newest, you must
> >> > + * reverse the order by yourself before traversing.
> >> > + */
> >> > +#define llist_for_each_safe(pos, n, node)   \
> >> > +for ((pos) = (node); (pos) && ((n) = (pos)->next, true); (pos) 
> >> > = (n))
> >> > +
> >> 
> >> Following the style of other xxx_for_each_safe,
> >> 
> >> #define llist_for_each_safe(pos, n, node)  \
> >>for (pos = (node), (pos && (n = pos->next)); pos; pos = n, n = 
> >> pos->next)
> >
> > Do you think it should be modified? I think mine is simpler. No?
> 
> Personally I prefer the style of other xxx_for_each_safe().

Yes, I will modify it as you recommand.

Thank you very much.

> 
> Best Regards,
> Huang, Ying
> 
> >> 
> >> Best Regards,
> >> Huang, Ying
> >> 
> >> > +/**
> >> >   * llist_for_each_entry - iterate over some deleted entries of 
> >> > lock-less list of given type
> >> >   * @pos:the type * to use as a loop cursor.
> >> >   * @node:   the fist entry of deleted list entries.

Re: [PATCH v2 1/9] llist: Provide a safe version for llist_for_each

[Byungchul Park]

On Mon, Feb 13, 2017 at 03:52:44PM +0800, Huang, Ying wrote:
> Byungchul Park  writes:
> 
> > On Mon, Feb 13, 2017 at 03:36:33PM +0800, Huang, Ying wrote:
> >> Byungchul Park  writes:
> >> 
> >> > Sometimes we have to dereference next field of llist node before entering
> >> > loop becasue the node might be deleted or the next field might be
> >> > modified within the loop. So this adds the safe version of 
> >> > llist_for_each,
> >> > that is, llist_for_each_safe.
> >> >
> >> > Signed-off-by: Byungchul Park 
> >> > ---
> >> >  include/linux/llist.h | 19 +++
> >> >  1 file changed, 19 insertions(+)
> >> >
> >> > diff --git a/include/linux/llist.h b/include/linux/llist.h
> >> > index fd4ca0b..4c508a5 100644
> >> > --- a/include/linux/llist.h
> >> > +++ b/include/linux/llist.h
> >> > @@ -105,6 +105,25 @@ static inline void init_llist_head(struct 
> >> > llist_head *list)
> >> >  for ((pos) = (node); pos; (pos) = (pos)->next)
> >> >  
> >> >  /**
> >> > + * llist_for_each_safe - iterate over some deleted entries of a 
> >> > lock-less list
> >> > + *   safe against removal of list entry
> >> > + * @pos:the  llist_node to use as a loop cursor
> >> > + * @n:  another type * to use as temporary storage
> >> 
> >> s/type */ llist_node/
> >
> > Yes.
> >
> >> 
> >> > + * @node:   the first entry of deleted list entries
> >> > + *
> >> > + * In general, some entries of the lock-less list can be traversed
> >> > + * safely only after being deleted from list, so start with an entry
> >> > + * instead of list head.
> >> > + *
> >> > + * If being used on entries deleted from lock-less list directly, the
> >> > + * traverse order is from the newest to the oldest added entry.  If
> >> > + * you want to traverse from the oldest to the newest, you must
> >> > + * reverse the order by yourself before traversing.
> >> > + */
> >> > +#define llist_for_each_safe(pos, n, node)   \
> >> > +for ((pos) = (node); (pos) && ((n) = (pos)->next, true); (pos) 
> >> > = (n))
> >> > +
> >> 
> >> Following the style of other xxx_for_each_safe,
> >> 
> >> #define llist_for_each_safe(pos, n, node)  \
> >>for (pos = (node), (pos && (n = pos->next)); pos; pos = n, n = 
> >> pos->next)
> >
> > Do you think it should be modified? I think mine is simpler. No?
> 
> Personally I prefer the style of other xxx_for_each_safe().

Yes, I will modify it as you recommand.

Thank you very much.

> 
> Best Regards,
> Huang, Ying
> 
> >> 
> >> Best Regards,
> >> Huang, Ying
> >> 
> >> > +/**
> >> >   * llist_for_each_entry - iterate over some deleted entries of 
> >> > lock-less list of given type
> >> >   * @pos:the type * to use as a loop cursor.
> >> >   * @node:   the fist entry of deleted list entries.

Re: [PATCH v2 1/9] llist: Provide a safe version for llist_for_each

[Huang, Ying]

Byungchul Park  writes:

> On Mon, Feb 13, 2017 at 03:36:33PM +0800, Huang, Ying wrote:
>> Byungchul Park  writes:
>> 
>> > Sometimes we have to dereference next field of llist node before entering
>> > loop becasue the node might be deleted or the next field might be
>> > modified within the loop. So this adds the safe version of llist_for_each,
>> > that is, llist_for_each_safe.
>> >
>> > Signed-off-by: Byungchul Park 
>> > ---
>> >  include/linux/llist.h | 19 +++
>> >  1 file changed, 19 insertions(+)
>> >
>> > diff --git a/include/linux/llist.h b/include/linux/llist.h
>> > index fd4ca0b..4c508a5 100644
>> > --- a/include/linux/llist.h
>> > +++ b/include/linux/llist.h
>> > @@ -105,6 +105,25 @@ static inline void init_llist_head(struct llist_head 
>> > *list)
>> >for ((pos) = (node); pos; (pos) = (pos)->next)
>> >  
>> >  /**
>> > + * llist_for_each_safe - iterate over some deleted entries of a lock-less 
>> > list
>> > + * safe against removal of list entry
>> > + * @pos:  the  llist_node to use as a loop cursor
>> > + * @n:another type * to use as temporary storage
>> 
>> s/type */ llist_node/
>
> Yes.
>
>> 
>> > + * @node: the first entry of deleted list entries
>> > + *
>> > + * In general, some entries of the lock-less list can be traversed
>> > + * safely only after being deleted from list, so start with an entry
>> > + * instead of list head.
>> > + *
>> > + * If being used on entries deleted from lock-less list directly, the
>> > + * traverse order is from the newest to the oldest added entry.  If
>> > + * you want to traverse from the oldest to the newest, you must
>> > + * reverse the order by yourself before traversing.
>> > + */
>> > +#define llist_for_each_safe(pos, n, node) \
>> > +  for ((pos) = (node); (pos) && ((n) = (pos)->next, true); (pos) = (n))
>> > +
>> 
>> Following the style of other xxx_for_each_safe,
>> 
>> #define llist_for_each_safe(pos, n, node)\
>>  for (pos = (node), (pos && (n = pos->next)); pos; pos = n, n = 
>> pos->next)
>
> Do you think it should be modified? I think mine is simpler. No?

Personally I prefer the style of other xxx_for_each_safe().

Best Regards,
Huang, Ying

>> 
>> Best Regards,
>> Huang, Ying
>> 
>> > +/**
>> >   * llist_for_each_entry - iterate over some deleted entries of lock-less 
>> > list of given type
>> >   * @pos:  the type * to use as a loop cursor.
>> >   * @node: the fist entry of deleted list entries.

Re: [PATCH v2 1/9] llist: Provide a safe version for llist_for_each

[Huang, Ying]

Byungchul Park  writes:

> On Mon, Feb 13, 2017 at 03:36:33PM +0800, Huang, Ying wrote:
>> Byungchul Park  writes:
>> 
>> > Sometimes we have to dereference next field of llist node before entering
>> > loop becasue the node might be deleted or the next field might be
>> > modified within the loop. So this adds the safe version of llist_for_each,
>> > that is, llist_for_each_safe.
>> >
>> > Signed-off-by: Byungchul Park 
>> > ---
>> >  include/linux/llist.h | 19 +++
>> >  1 file changed, 19 insertions(+)
>> >
>> > diff --git a/include/linux/llist.h b/include/linux/llist.h
>> > index fd4ca0b..4c508a5 100644
>> > --- a/include/linux/llist.h
>> > +++ b/include/linux/llist.h
>> > @@ -105,6 +105,25 @@ static inline void init_llist_head(struct llist_head 
>> > *list)
>> >for ((pos) = (node); pos; (pos) = (pos)->next)
>> >  
>> >  /**
>> > + * llist_for_each_safe - iterate over some deleted entries of a lock-less 
>> > list
>> > + * safe against removal of list entry
>> > + * @pos:  the  llist_node to use as a loop cursor
>> > + * @n:another type * to use as temporary storage
>> 
>> s/type */ llist_node/
>
> Yes.
>
>> 
>> > + * @node: the first entry of deleted list entries
>> > + *
>> > + * In general, some entries of the lock-less list can be traversed
>> > + * safely only after being deleted from list, so start with an entry
>> > + * instead of list head.
>> > + *
>> > + * If being used on entries deleted from lock-less list directly, the
>> > + * traverse order is from the newest to the oldest added entry.  If
>> > + * you want to traverse from the oldest to the newest, you must
>> > + * reverse the order by yourself before traversing.
>> > + */
>> > +#define llist_for_each_safe(pos, n, node) \
>> > +  for ((pos) = (node); (pos) && ((n) = (pos)->next, true); (pos) = (n))
>> > +
>> 
>> Following the style of other xxx_for_each_safe,
>> 
>> #define llist_for_each_safe(pos, n, node)\
>>  for (pos = (node), (pos && (n = pos->next)); pos; pos = n, n = 
>> pos->next)
>
> Do you think it should be modified? I think mine is simpler. No?

Personally I prefer the style of other xxx_for_each_safe().

Best Regards,
Huang, Ying

>> 
>> Best Regards,
>> Huang, Ying
>> 
>> > +/**
>> >   * llist_for_each_entry - iterate over some deleted entries of lock-less 
>> > list of given type
>> >   * @pos:  the type * to use as a loop cursor.
>> >   * @node: the fist entry of deleted list entries.

Re: [PATCH v2 1/9] llist: Provide a safe version for llist_for_each

[Byungchul Park]

On Mon, Feb 13, 2017 at 03:36:33PM +0800, Huang, Ying wrote:
> Byungchul Park  writes:
> 
> > Sometimes we have to dereference next field of llist node before entering
> > loop becasue the node might be deleted or the next field might be
> > modified within the loop. So this adds the safe version of llist_for_each,
> > that is, llist_for_each_safe.
> >
> > Signed-off-by: Byungchul Park 
> > ---
> >  include/linux/llist.h | 19 +++
> >  1 file changed, 19 insertions(+)
> >
> > diff --git a/include/linux/llist.h b/include/linux/llist.h
> > index fd4ca0b..4c508a5 100644
> > --- a/include/linux/llist.h
> > +++ b/include/linux/llist.h
> > @@ -105,6 +105,25 @@ static inline void init_llist_head(struct llist_head 
> > *list)
> > for ((pos) = (node); pos; (pos) = (pos)->next)
> >  
> >  /**
> > + * llist_for_each_safe - iterate over some deleted entries of a lock-less 
> > list
> > + *  safe against removal of list entry
> > + * @pos:   the  llist_node to use as a loop cursor
> > + * @n: another type * to use as temporary storage
> 
> s/type */ llist_node/

Yes.

> 
> > + * @node:  the first entry of deleted list entries
> > + *
> > + * In general, some entries of the lock-less list can be traversed
> > + * safely only after being deleted from list, so start with an entry
> > + * instead of list head.
> > + *
> > + * If being used on entries deleted from lock-less list directly, the
> > + * traverse order is from the newest to the oldest added entry.  If
> > + * you want to traverse from the oldest to the newest, you must
> > + * reverse the order by yourself before traversing.
> > + */
> > +#define llist_for_each_safe(pos, n, node)  \
> > +   for ((pos) = (node); (pos) && ((n) = (pos)->next, true); (pos) = (n))
> > +
> 
> Following the style of other xxx_for_each_safe,
> 
> #define llist_for_each_safe(pos, n, node) \
>   for (pos = (node), (pos && (n = pos->next)); pos; pos = n, n = 
> pos->next)

Do you think it should be modified? I think mine is simpler. No?

> 
> Best Regards,
> Huang, Ying
> 
> > +/**
> >   * llist_for_each_entry - iterate over some deleted entries of lock-less 
> > list of given type
> >   * @pos:   the type * to use as a loop cursor.
> >   * @node:  the fist entry of deleted list entries.

Re: [PATCH v2 1/9] llist: Provide a safe version for llist_for_each

[Byungchul Park]

On Mon, Feb 13, 2017 at 03:36:33PM +0800, Huang, Ying wrote:
> Byungchul Park  writes:
> 
> > Sometimes we have to dereference next field of llist node before entering
> > loop becasue the node might be deleted or the next field might be
> > modified within the loop. So this adds the safe version of llist_for_each,
> > that is, llist_for_each_safe.
> >
> > Signed-off-by: Byungchul Park 
> > ---
> >  include/linux/llist.h | 19 +++
> >  1 file changed, 19 insertions(+)
> >
> > diff --git a/include/linux/llist.h b/include/linux/llist.h
> > index fd4ca0b..4c508a5 100644
> > --- a/include/linux/llist.h
> > +++ b/include/linux/llist.h
> > @@ -105,6 +105,25 @@ static inline void init_llist_head(struct llist_head 
> > *list)
> > for ((pos) = (node); pos; (pos) = (pos)->next)
> >  
> >  /**
> > + * llist_for_each_safe - iterate over some deleted entries of a lock-less 
> > list
> > + *  safe against removal of list entry
> > + * @pos:   the  llist_node to use as a loop cursor
> > + * @n: another type * to use as temporary storage
> 
> s/type */ llist_node/

Yes.

> 
> > + * @node:  the first entry of deleted list entries
> > + *
> > + * In general, some entries of the lock-less list can be traversed
> > + * safely only after being deleted from list, so start with an entry
> > + * instead of list head.
> > + *
> > + * If being used on entries deleted from lock-less list directly, the
> > + * traverse order is from the newest to the oldest added entry.  If
> > + * you want to traverse from the oldest to the newest, you must
> > + * reverse the order by yourself before traversing.
> > + */
> > +#define llist_for_each_safe(pos, n, node)  \
> > +   for ((pos) = (node); (pos) && ((n) = (pos)->next, true); (pos) = (n))
> > +
> 
> Following the style of other xxx_for_each_safe,
> 
> #define llist_for_each_safe(pos, n, node) \
>   for (pos = (node), (pos && (n = pos->next)); pos; pos = n, n = 
> pos->next)

Do you think it should be modified? I think mine is simpler. No?

> 
> Best Regards,
> Huang, Ying
> 
> > +/**
> >   * llist_for_each_entry - iterate over some deleted entries of lock-less 
> > list of given type
> >   * @pos:   the type * to use as a loop cursor.
> >   * @node:  the fist entry of deleted list entries.

Re: [PATCH v2 1/9] llist: Provide a safe version for llist_for_each

[Huang, Ying]

Byungchul Park  writes:

> Sometimes we have to dereference next field of llist node before entering
> loop becasue the node might be deleted or the next field might be
> modified within the loop. So this adds the safe version of llist_for_each,
> that is, llist_for_each_safe.
>
> Signed-off-by: Byungchul Park 
> ---
>  include/linux/llist.h | 19 +++
>  1 file changed, 19 insertions(+)
>
> diff --git a/include/linux/llist.h b/include/linux/llist.h
> index fd4ca0b..4c508a5 100644
> --- a/include/linux/llist.h
> +++ b/include/linux/llist.h
> @@ -105,6 +105,25 @@ static inline void init_llist_head(struct llist_head 
> *list)
>   for ((pos) = (node); pos; (pos) = (pos)->next)
>  
>  /**
> + * llist_for_each_safe - iterate over some deleted entries of a lock-less 
> list
> + *safe against removal of list entry
> + * @pos: the  llist_node to use as a loop cursor
> + * @n:   another type * to use as temporary storage

s/type */ llist_node/

> + * @node:the first entry of deleted list entries
> + *
> + * In general, some entries of the lock-less list can be traversed
> + * safely only after being deleted from list, so start with an entry
> + * instead of list head.
> + *
> + * If being used on entries deleted from lock-less list directly, the
> + * traverse order is from the newest to the oldest added entry.  If
> + * you want to traverse from the oldest to the newest, you must
> + * reverse the order by yourself before traversing.
> + */
> +#define llist_for_each_safe(pos, n, node)\
> + for ((pos) = (node); (pos) && ((n) = (pos)->next, true); (pos) = (n))
> +

Following the style of other xxx_for_each_safe,

#define llist_for_each_safe(pos, n, node)   \
for (pos = (node), (pos && (n = pos->next)); pos; pos = n, n = 
pos->next)

Best Regards,
Huang, Ying

> +/**
>   * llist_for_each_entry - iterate over some deleted entries of lock-less 
> list of given type
>   * @pos: the type * to use as a loop cursor.
>   * @node:the fist entry of deleted list entries.

Re: [PATCH v2 1/9] llist: Provide a safe version for llist_for_each

[Huang, Ying]

Byungchul Park  writes:

> Sometimes we have to dereference next field of llist node before entering
> loop becasue the node might be deleted or the next field might be
> modified within the loop. So this adds the safe version of llist_for_each,
> that is, llist_for_each_safe.
>
> Signed-off-by: Byungchul Park 
> ---
>  include/linux/llist.h | 19 +++
>  1 file changed, 19 insertions(+)
>
> diff --git a/include/linux/llist.h b/include/linux/llist.h
> index fd4ca0b..4c508a5 100644
> --- a/include/linux/llist.h
> +++ b/include/linux/llist.h
> @@ -105,6 +105,25 @@ static inline void init_llist_head(struct llist_head 
> *list)
>   for ((pos) = (node); pos; (pos) = (pos)->next)
>  
>  /**
> + * llist_for_each_safe - iterate over some deleted entries of a lock-less 
> list
> + *safe against removal of list entry
> + * @pos: the  llist_node to use as a loop cursor
> + * @n:   another type * to use as temporary storage

s/type */ llist_node/

> + * @node:the first entry of deleted list entries
> + *
> + * In general, some entries of the lock-less list can be traversed
> + * safely only after being deleted from list, so start with an entry
> + * instead of list head.
> + *
> + * If being used on entries deleted from lock-less list directly, the
> + * traverse order is from the newest to the oldest added entry.  If
> + * you want to traverse from the oldest to the newest, you must
> + * reverse the order by yourself before traversing.
> + */
> +#define llist_for_each_safe(pos, n, node)\
> + for ((pos) = (node); (pos) && ((n) = (pos)->next, true); (pos) = (n))
> +

Following the style of other xxx_for_each_safe,

#define llist_for_each_safe(pos, n, node)   \
for (pos = (node), (pos && (n = pos->next)); pos; pos = n, n = 
pos->next)

Best Regards,
Huang, Ying

> +/**
>   * llist_for_each_entry - iterate over some deleted entries of lock-less 
> list of given type
>   * @pos: the type * to use as a loop cursor.
>   * @node:the fist entry of deleted list entries.